$background-color-theme: red;
$background-color-theme1: blue;
$background-color-theme2: green;
$color-them1:red;
$color-them2:yellow;

@mixin bg_color($color){
  background-color: $color;
  [data-theme="theme1"] & {
    background-color: $background-color-theme1;
  }
  [data-theme="theme2"] & {
    background-color: $background-color-theme2;
  }
}

@mixin txt_color($color){
  color: #000;
  [data-theme="theme1"] & {
   color:$color-them1;
  }
  [data-theme="theme2"] & {
   color:$color-them2;
  }
}